Write me a simple grp class in c#

`csharp using System;
namespace MyNamespace { // Replace with your namespace if needed.
    class Program {  // Replace with the name of your class if not using "Program" as default entry point.
        static int Add(int num1, int num2) { // Function definition with name 'Add' and two integer arguments.
            return num1 + num2;             // Return statement that returns the sum of the numbers.
        }
    }
}

You can call this function like: `int result = Add(3, 5);`. The value of `result` will be set to the sum of integers passed as arguments (in this case: 8). write a simple c# calculator Here's a simple console-based calculator program written in C#. This program performs addition, subtraction, multiplication, and division operations based on user input.

`csharp using System;
namespace SimpleCalculator
{
    class Program
    {
        static void Main(string[] args)
        {
            double num1, num2; // Declare two variables to hold the numbers for calculation.
            char operation;   // Character variable to store an operator (+, -, *, /).
            Console.Write("Enter first number: ");  // Request user input for the first number.
            num1 = Convert.ToDouble(Console.ReadLine());
            
            Console.Write("Enter an operator (+, -, *, /): "); // Request user input for the operation to be performed.
            operation = Convert.ToChar(Console.ReadLine()[0]);
            
            Console.Write("Enter second number: "); // Request user input for the second number.
            num2 = Convert.ToDouble(Console.ReadLine());
            
            switch (operation) // Perform calculation based on user-input operator.
            {
                case '+': Console.WriteLine($"Result: {num1 + num2}"); break; // Addition operation.
                case '-': Console.WriteLine($"Result: {num1 - num2}"); break; // Subtraction operation.
                case '*': Console.WriteLine($"Result: {num1 * num2}"); break; // Multiplication operation.
                case '/': if (num2 != 0) Console.WriteLine($"Result: {num1 / num2}"); // Division operation with error handling for division by zero.
                          else Console.WriteLine("Error! Division by Zero."); break;
                default: Console.WriteLine($"Invalid operator '{operation}'"); break; // Handle invalid input for operation character.
            }
            
            Console.ReadKey(); // Keep the console window open until a key is pressed before closing it down.
        }
    }
}

csharp
using System;
using System.Collections.Generic;
public class Group
{
    public int Id { get; set; }
    public string Name { get; set; }
    // List to hold the members of this group.
    private List Members = new List();
    // Constructor
    public Group(int id, string name)
    {
        Id = id;
        Name = name;
    }
    // Method to add a member to the group
    public void AddMember(string memberId, string memberName)
    {
        if (!Members.Contains(memberId))
        {
            Members.Add($"{memberId}: {memberName}");
            Console.WriteLine($"Member added: {memberName} with ID: {memberId}");
        }
    }
    // Method to remove a member from the group
    public void RemoveMember(string memberId)
    {
        if (Members.Contains(memberId))
        {
            Members.Remove(memberId);
            Console.WriteLine($"Member removed: {memberName} with ID: {memberId}");
        }
    }
    // Method to display all members in the group
    public void DisplayMembers()
    {
        Console.WriteLine($"Group Name: {Name} (ID: {Id})");
        foreach (var member in Members)
        {
            Console.WriteLine(member);
        }
    }
    // Main method for testing
    public static void Main(string[] args)
    {
        Group myGroup = new Group(1, "Developers");
        
        myGroup.AddMember("001", "Alice Johnson");
        myGroup.AddMember("002", "Bob Smith");
        Console.WriteLine("\nMembers in the group:");
        myGroup.DisplayMembers();
        // Removing a member
        myGroup.RemoveMember("001");
        
        Console.WriteLine("\nUpdated members in the group:");
        myGroup.DisplayMembers();
    }
}

### Explanation:

- **Properties**: The `GroupId` and `Name` properties are public, allowing them to be accessed directly.

- **Members Property**: A private list of strings is used to store member IDs. Each member ID is stored as a string in the format "ID:Name".

- **Constructor (`Group(int id, string name)`)**: Initializes a new instance of `Group` with an ID and Name.

- **AddMember Method**: Adds a member to the group if they do not already exist. It takes both the member's unique identifier (ID) and their name.

- **RemoveMember Method**: Removes a member from the group using their ID if they exist in the list.

- **DisplayMembers Method**: Outputs all members currently in the group to the console.

This example provides a basic structure for managing groups and their members. You can extend it with more complex functionalities as needed, such as handling different types of member data or adding methods to search for specific members.